This invention relates to ink-jet printing devices, and more particularly to techniques for associating media type and roll length with media rolls.
Printers and plotters in use today for printing text/graphics typically have the capability of printing on various types of print media, such as plain paper, special papers such as coated paper, matte paper, and the like, as well as various non-paper media such as velum, film etc. Printer parameter modifications vary with the type of media, and can include changes in color maps and print modes. The printers and plotters typically include sensors for sensing the presence of the print medium in the media path, and the medium edges.
Large scale plotters typically support roll-form print media, i.e., a supply of paper or transparent film on a roll. One such device is the Design Jet product family of large scale plotters marketed by Hewlett-Packard Company. A cutter is employed to cut the medium after the plot is completed so that the finished plot is separated from the roll.
If one could predict the end of a media roll, the printer could be left printing alone overnight, thus substantially increasing the unattendedness capability of the printer. With the Design Jet 2500 CP, with 400 cc of ink per cartridge, the unattendedness limitation from uncertainty about the remaining media quantity is even more a problem.
Typically, there are two types of information that a large format printer would like to know from the media roll, its type (coated, glossy, etc.) and its remaining length. The first type of information is used for applying the correct print modes to each media type. The second is needed to know so that one does not run out of media in the middle of a plot.
The conventional approach for providing the first type of information to the printer is through a manual input. Thus, the user may use a display panel on the printer (or a dialogue box in the printer driver that is resident on the host computer). This action involves the user scrolling through a list of displayed media types, until one appears which matches the media type to be loaded on the printer. The user selects the media when loading the media roll, and the printer controller automatically establishes printer parameters in accordance with the selection. The printer will present as a default the media type that was most recently used, and because a reduced set of media types was typically supported, the manual input process was in the past not very burdensome or limiting.
As for the media length, the printer could be counting the length of media it has been printing on, and so it would be theoretically possible to tell the user when the media roll is reaching its end, just by telling the printer the initial length of the media roll. The problems here start when a user decides to unload a media roll before it has ended, in order, for example, to print onto another kind of media. In this case, the media length information that the printer may have recorded gets lost. This information is key to being able to resume length counting when the media roll is reloaded. Thus, the ability to unload a partially used media roll and re-load it at some later time has made the task of predicting the roll""s end unfeasible.
It would therefore be advantageous to allow media type information and/or remaining media quantity to be retrieved by the printer from a media roll without any user intervention.
It would further be advantageous to present the media type information and/or remaining media quantity in a human-readable form on a partially used roll.
A method is described for identifying at least a media length value for a roll-type media to be printed upon to a printer controller in a printer. The method includes, in one embodiment, keeping track of the length of media used during printing operations, prior to removing the roll from the printer, printing an indicia on a remaining portion of the roll which identifies at least the remaining length of the print medium, or information from which the remaining length can be determined, such as the length previously used from the roll, removing the roll from the printer, installing the removed roll from the printer, reading the indicia to determine the remaining length of the media, and using the remaining length information during subsequent printing operations using the removed roll. The indicia can be in human-readable form, and the user after reading the remaining length data, manually inputs this information into the printer through a control panel or other input device. The printer controller thus obtains the length information corresponding to the reloaded roll. The indicia can also be printed on the roll in a machine-readable form, and the printer can read the data as the roll is reloaded into the printer.
According to another aspect of the invention, the data is encoded as a grayscale code which is read by the printer""s optical sensor. The indicia can include media type information and media length information in machine readable form, and a human-readable portion showing the length of the roll.
According to another aspect, the indicia can include a user-defined code identifying the media.